Proposed Grayson Repowering Project

What is Repowering?

Ifttfkbusqsywy0dlrmy aerial

Repowering is a common term among electric utilities that refers to rebuilding power plants by taking an old generating unit out of commission, dismantling it, and building a new, modern one at the same plant. The repowered units are more energy efficient, create less emissions, and increase reliability of the power grid. 

The City of Glendale, Department of Water and Power is proposing to repower the Grayson Power Plant located in an industrial area of the City of Glendale.  A majority of the facilities located at the Grayson Power Plant, were completed between 1941 and 1977, and are proposed to be replaced with more reliable, efficient, flexible, and cleaner units.  

Proposed Project

R9hemnlursewyw5wgkfq grayson power plant eir figure aerial updated with uoc 11.21.16

The Project site is located in an industrial area of the City of Glendale at 800 Air Way, Glendale, CA 91201, just northeast of the Interstate 5 and Highway 134 interchange.  The site is bounded to the south by the Verdugo Wash and Highway 134, to the west by the Los Angeles River and Interstate 5, to the north by commercial properties and to the east by commercial and residential properties. The site is currently used as the Grayson Power Plant. The Grayson Repowering Project would be located entirely within the existing Grayson Power Plant, an operating power plant. 



The Grayson Power Plant, named after the City's first Chief Engineer and General Manager Loren Grayson, has been faithfully serving the electrical power needs of the City of Glendale since 1941. Prior to 1937, the City purchased all of its electrical power from the Pacific Light and Power Company (today known as Southern California Edison). That same year after evaluating the current and future electrical needs of the Glendale community, the City not only entered into an agreement to purchase hydroelectric power from the Hoover Dam Project but also made a decision to establish a City owned and operated steam powered electrical generating facility. Construction of the new facility began in 1939 and the first generating unit went into service in 1941. Since that time the facility has been expanded to meet the growing needs of the residents and businesses in the City and has proven to be an invaluable asset to both GWP and more importantly to their customers. However, over time due to age and normal degradation of the equipment, the reliability, efficiency and cost effectiveness of the facility has steadily and continuously declined. Recognizing the tremendous benefit that locally generated power has provided our City and seeing the long term benefits that would be derived from replacing the existing units not only from an efficiency and cost perspective but also an environmental quality standpoint, the City has embarked on a process for the potential replacement/repowering of the existing facility.


Djtpxw4ttyhyudat6kpn 1

The Grayson Repowering Project is necessary to meet current and future energy needs and to meet the Renewable Power Standards (RPS) mandate. The Grayson Repowering Project will achieve the following benefits: 

  • Maintain reliable service.
  • Keep rates affordable to Glendale ratepayers. 
  • Comply with state regulations regarding renewable energy supplies and greenhouse gas emissions.
  • Replace the aged, unreliable, inefficient, high maintenance steam boilers with new efficient and more environmentally responsible generation technologies. 
  • Provide a locally controlled source of generation to minimize the City’s reliance on importing power from remote generation locations.
  • Support water conservation efforts by eliminating the use of potable water for generation purposes.

Stay Connected



Vtd1yvcwqaco8pzkhbvr grayson demolition figure 1

The City is proposing to replace all the existing generation facilities and their related infrastructure, with the exception of Unit 9, by removing existing aboveground and belowground equipment, and facilities and building new generation facilities.  This includes demolishing the Grayson Power Plant Boiler Building, replacing Cooling Towers 1 through 5, and replacing the generation units, designated as Unit 8A and 8B/C. The existing generation facilities (with the exception of Unit 9) would be replaced with a combination of combined cycle and simple cycle gas turbine generation units. 

Notice of Preparation


Initial Study


Site Plan

Ekuxuhkbtayuqxxwjyap grayson aerial

The primary objective of the Project is to replace the aged, inefficient, inflexible, and unreliable generation units at Grayson Power Plant with approximately 260 megawatt (MW) net modern power generation that is efficient, reliable, operationally flexible, and that can easily integrate into the City of Glendale’s power system. This Project would ensure system reliability, balance renewable imports, and meet the power needs of the City in the event that the importing capacity from external transmission lines is not available to serve its load. 

Before & After






Past Meetings/Events

January 12, 2017
Scoping Meeting for the Environmental Impact Report

Giffith Manor Park
1551 Flower St.
Glendale, CA 91201

January 25, 2017
3:30 p.m. - 4:30 p.m.
Meeting with the Pelanconi Homeowners Association

Grayson Power Plant Training Room
800 Air Way
Glendale, CA 91201


February 21, 2017
12:00 p.m. - 1:00 p.m.
Meeting with the Chamber of Commerce

Chamber of Commerce Offices
701 N. Brand Blvd. Suite 120
Glendale, CA 91203


March 6, 2017

7:00 p.m. - 8:00 p.m.
Meeting with the Homeowners Coordinating Council

Verdugo Hills Council Boy Scouts of America
1325 Grandview Ave.
Glendale, CA 91202


October 16, 2017
6:00 p.m.
Special Meeting of the Glendale Water & Power Commission on the Draft Environmental Impact Report

Glendale City Council Chambers
613 E. Broadway, 2nd Floor
Glendale, CA 91206


October 19, 2017
6:00 p.m.
Community Meeting about the Draft Environmental Impact Report

GWP Utility Operations Center Training Room
800 Air Way
Glendale, CA 91201




The City of Glendale, Department of Water and Power (City) is proposing to repower the Grayson Power Plant (Project), located in an industrial area of the City of Glendale at 800 Air Way, Glendale, California 91201, just northeast of the Interstate 5 and Highway 134 interchange.  A majority of the facilities located at the Grayson Power Plant, with the exception of Unit 9 (a simple cycle peaking plant built in 2003), were completed between 1941 and 1977, and are proposed to be replaced with more reliable, efficient, flexible, and cleaner units and related facilities and infrastructure.  The City is proposing to replace all the existing generation facilities, units, and their related infrastructure, with the exception of Unit 9, by removing existing aboveground and belowground equipment, and facilities and building new generation facilities.  This includes demolishing the Grayson Power Plant Boiler Building, replacing Cooling Towers 1 through 5, and replacing the generation units, designated as Unit 8A and 8B/C. The existing generation facilities (with the exception of Unit 9) would be replaced with a combination of combined cycle and simple cycle gas turbine generation units.

The Project would be located entirely within the existing Grayson Power Plant, an operating power plant. The site is bounded to the south by the Verdugo Wash and Highway 134, to the west by the Los Angeles River and Interstate 5, to the north by commercial properties, and to the east by commercial and residential properties. The approximate coordinates of the Project are 34° 09’ 19” N and 118° 16’ 42” W.

Purpose and Need

The proposed repowering of the Grayson Power Plant is necessary to meet current and future City energy needs and California Renewables Portfolio Standard (RPS) requirements. Pursuant with Senate Bill 350 that was signed into legislation in October 2015, the RPS requires retail sellers and publicly owned utilities including GWP to procure 50 percent of their electricity from eligible renewable energy resources by 2030. The City serves its power system load through a combination of renewable energy sources (both local and imports), non-renewable imports, and local generation.  The City system’s single largest contingency is nominally 100 megawatts (MW) based on imported power through the maximum City allocation on the 500 kilovolt (kV) Pacific Direct Current (DC) Intertie (Path 65).

In order to meet retail power load obligations, Glendale Water and Power (GWP) relies on a combination of both local and remote generation, as well as long-term power purchase agreements and spot market purchases from a variety of suppliers throughout the Western Electricity Coordination Council (WECC) territory, including the California Independent System Operator (CAISO).  Natural gas for generation is supplied by several sources, which include gas reserves in Wyoming, a pre-paid gas commodity contract, and the daily gas market.  Landfill gas for generation at Grayson is supplied via dedicated pipeline from the Scholl Canyon Landfill in the City of Glendale.  GWP also uses transmission and generation rights to take advantage of arbitrage opportunities and to transact with counterparties in the wholesale market. As a result of recent state mandates, GWP is becoming more involved in short and long-term markets for renewable energy and carbon allowances.  GWP operates within the Balancing Area of the Los Angeles Department of Water and Power.

In June 2015, GWP completed its Integrated Resource Plan (IRP) that identified 262 megawatts (MW) of local generation at the existing Grayson Power Plant site as the best option to meet regulatory requirements for reliability. GWP has proposed to repower the exisiting Grayson Power Plant on the existing plant Site. The Project would replace 238 MW of the existing capacity from the boiler units (Unit Nos. 3, 4, 5) and combined cycle units (Unit Nos. 1, 2, 8A and 8B/C) with more efficient generation. Unit No. 9 commissioned in 2003, would remain. The project would comprise two 50 MW simple cycle units and two 75 MW one-on-one combined cycle units. Unit size is limited so that minimum generation levels would closely match the City's internal generation needs under low system load conditions.The simple and combined cycle unit sizes are also strongly influenced by the City's intent to self-supply spinning and non-spinning reserve and to integrate future renewable resources to meet state regulatory requirements for increasing procurement of renewable energy resources.

The Proposed Biogas Generation Project

Landfill gas is considered a renewable energy resource. Currently this landfill gas is located at an existing Class III nonhazardous landfill that has been accepting waste since the 1960’s. This waste is naturally decomposing and producing landfill gas that includes methane, a greenhouse gas that is combustible and can be put to beneficial use. This will help the City of Glendale achieve the State of California mandate that every utility shall provide a certain portion of renewable energy to their electric generation portfolio. By converting landfill gas to renewable energy the City can receive 100% renewable credit for the energy produced. Currently, the City is blending the methane gas with natural gas to produce electricity at the existing Grayson Power Plant boilers. The City is only receiving 50% credit for the renewable energy produced because the landfill gas is blended with natural gas, which is not a renewable resource. The City will produce and receive 100% renewable credit by installing generation units that can directly burn the landfill gas at the project site. Combusting and producing electricity at the landfill site will enable the City of Glendale to decommission the approximately five-mile pipeline between the landfill site and the Grayson Power Plant.

Currently, the landfill gas is collected at a central location within the project site where it is compressed, liquids are removed, and the landfill gas is piped to the Grayson Power Plant via an underground dedicated pipeline approximately five-miles in length where it is blended with natural gas then used as fuel in the boilers to make steam to generate electricity for the City of Glendale. The Grayson Power Plant is being repowered and the new turbines cannot use the landfill gas as fuel. The landfill gas is constantly being produced at the landfill and there are only two options currently available: burn it in the air by flares or put the landfill gas to beneficial use by using it as fuel for the generation of renewable electricity.

For more information on the Proposed Biogas Renewable Generation Project click here.


RFP for an Integrated Resource Plan (IRP) consultant and an Owner's Engineer (OE) February 2014 Complete
Award Contract for an IRP consultant and OE August 2014 Complete
Develop and Complete an IRP June 2015 Complete
Decision Point: Determine ultimate configuration of Grayson Power Plant June 2015 Complete
Engineering for permitting and environmental assessments July 2015 - May 2018 In Progress
RFP process and selection of Bond Counsel and Financial Services Advisor February 2016 Complete

Decision Point: RFP for Power Island Equipment (PIE)

January 2016 Complete
Decision Point: Award a Limited Notice-to-Proceed (LNTP) Contract for PIE November 2016 Complete
RFQ for Engineering, Procurement, and Construction (EPC) contractors February 2017 Complete
Approval of a Project Labor Agreement (PLA) February 2017 Complete
RFP issued for an EPC contractor August 2017 Complete
Draft Environmental Impact Report Comment Period September 18, 2017 - November 20, 2017 Complete
Request for Bid for a Demolition contractor December 2017  
City Council Meeting for EIR Certification March 2018  
CEQA Process Complete, City Council adopts FEIR March 2018  
Decision Point: Approve Project and Proceed with Debt Issuance March 2018  
Award All Contracts May 2018  
Start of Demolition June 2018  
Start of Construction March 2019  
Commercial Operation Summer 2021  






Proposed Grayson Repowering Project Frequently Asked Questions

Are you expanding the Grayson Power Plant?

No, Glendale Water & Power (GWP) is not going to expand the Grayson Power Plant. The driving force for replacing the obsolete Units 1-5 and 8* at the Grayson Power Plant is to ensure a reliable electric supply for the citizens and residents of the City of Glendale. A majority of the facilities located at the Grayson Power Plant were completed between 1941 and 1977, and must be replaced. We are proposing to rebuild substantial portions of the plant by taking old generating units out of commission, dismantling them, and building new, modern units in their place. This process is called repowering. The new repowered units will be cleaner, more energy efficient, and will greatly increase the reliability of the Glendale’s power grid.

* units 6 and 7 were retired several years ago and dismantled. Unit 9 is about 15 years old and will continue to operate.

How is GWP going to pay for the repowering of the Grayson Power Plant?

GWP is proposing to finance the repowering project which has an estimated cost of $500 million, through the issuance of revenue bonds. GWP sells bonds to finance capital projects, and the payments for the GWP bonds are covered by the revenue that GWP receives from its customers based on its rate schedule. The tax revenues that the City receives are not used to pay off GWP bonds. The final cost will not be determined until the detailed design is finalized.

The repowering will not impact rates. The cost of generation at the repowered plant will be less (more efficient units burn less natural gas to produce the same amount of energy), and for short-term energy needs, the new units can deliver energy more cheaply than spot market (emergency) power purchases that must be imported with their associated transmission costs. Additionally, the new units will be able to provide reserves (on-line generation that can respond to losses in supply) more cheaply than purchasing and importing reserve capacity from other sources. These savings will pay for the bonds.

What if the City does not repower the Grayson Power Plant?

Units (1, 2, 3, 4, 5, and 8) are all 40 to 70 years old, are not expected to continue running much longer, and maintenance on these units is temporary and very costly. In addition, forthcoming air quality regulations will require GWP to do expensive retrofits, or shut down the plant within the next few years. If GWP does not repower the Grayson Power Plant, our sources of supply will be limited to purchased power, which is not always guaranteed and is very costly with extreme increases in costs for spot market purchases.

Is GWP repowering Grayson to generate excess power in order to sell it for profit?

No, the proposed repower is to meet the City’s energy needs and to ensure that there is a reliable source of power for Glendale. GWP is not repowering to sell energy for a profit. The capacity of the Grayson repower was driven solely by the reliability needs of Glendale and minimizing rate impacts to GWP customers.

Glendale doesn’t need this much power. Why are you building such a large plant? Do we really need this much? 

The capacity of the Grayson Repowering Project is driven to reliably serve the needs of the residents and businesses of Glendale. Without the Grayson repowering and after Units 1-8 are no longer capable of running, the available capacity through imports from outside sources and the one newer unit at Grayson Power Plant—Unit 9—is 287 MW. 

GWP must have in place sufficient reserve sources of power to cover the “loss of the single largest contingency”. This means that we must maintain enough generating capacity to power the City even if there is an unexpected failure or loss of our largest single source of power. For GWP, the largest single source of power is the DC Intertie line, which transmits 100 MW of power to the City. See image of GWP’s sources of power here. In fact, partial and complete loss of the DC Intertie line has occurred in the past, and some of the outages have been for extended periods of time. In addition, reserves must also be in place to re-establish reserves within one hour. With the loss of GWP’s single largest contingency, the City would have only 187 MW of supply available for meeting its obligations.  

GWP’s system load exceeds 187 MW more than 80 days a year. With respect to a peak day, GWP’s peak load is 350 MW (with no allowance for reserve margin) and there would be a shortfall of 163 MW that would have to be supplied by resources internal to the City. 

The Grayson Power Plant, once repowered, would add a capacity of 262 MW at average annual conditions (64° F). On a hot day (95° F), that capacity would fall to 242 MW. On the peak load day (100°+ F), the available additional capacity would be slightly less.

With 242 MW available at Grayson Power Plant, the City would have approximately 80 MW remain as reserve capacity. Thus, the Grayson Repower allows GWP to reliably serve Glendale by providing sufficient capacity to cover the loss of the single largest contingency and still meet load, as well as the non-operating reserve that could be started to provide the required spinning reserve.

Additionally, as GWP imports increasing amounts of wind, solar and other variable sources of renewable energy into the City, and as more solar power is generated locally in Glendale, this creates increased fluctuations on the power grid. A steady, constant source of energy such as that from the Grayson Power Plant is needed to balance out (“firm and shape”) the energy so that that a smooth and steady supply of power can be delivered to GWP customers. The old units at the Grayson Power Plant do not have the ability to rapidly adjust up and down to account for variances in solar output, based upon weather patterns on a minute-per-minute basis. Modernizing Grayson will allow us to manage renewable energy flows dynamically, so that energy deliveries will continue to be reliable.

Will GWP install any renewable energy sources at Grayson?

Yes, GWP will be placing solar panels onto the new buildings at the Grayson Power Plant, totaling approximately a ½ MW. GWP also plans to install 40 MW/80 Megawatt-hours (MWh)*** of short-term battery energy storage for regulation purposes at Grayson to reduce short-term cycling of the units. This will be done after the power plant is repowered. GWP is a leader within California in supplying renewable and carbon-free electricity. In 2016 GWP sourced 64% of the energy it supplied to Glendale from carbon-free sources (compared to 44% for all of California). Glendale is already close to meeting the requirement for 2030 that publicly-owned utilities procure 50 percent of their electricity from eligible renewable energy resources. Today, far ahead of the 2030 target date, Glendale procures 47 percent of its electricity from eligible renewable energy resources. GWP is committed to renewable energy and continues to expand our programs to use more solar and wind power.

*** A megawatt hour (MWh) equals 1,000 kilowatts of electricity used for one hour.

Will potable water be used as part of the repowered Grayson Plant?

The Grayson Power Plant would use recycled water for all process and cooling water requirements. The main use for recycled water includes boiler water makeup, cooling tower makeup, turbine power enhancement and cleaning, and NOx control for the simple cycle units. Recycled water would also be used for Unit 9 in place of potable water currently being used. The use of recycled water would eliminate the need for 20 acre-feet of ground water from wells in Glendale and 41 acre-feet of potable water currently being used, which is also water efficient and helps improve the City’s overall water conservation efforts. 

California’s cap and trade program requires all power producers to pay a cost per ton of CO2 emitted. Is the cost being underestimated?  

The cost of greenhouse gas credits would be incurred by Glendale whenever they use electricity from fossil fuel resources, whether GWP generates it or it is imported over the transmission system. Fossil fuel resources will be required until systems of energy storage have been proven on a utility scale for a utility such as GWP. The operating costs would therefore be incurred either way. Intermittent renewable purchase contracts also include a portion of fossil fuel generation.

Does the Grayson Power Plant sit on a mapped Liquefaction Hazard Zone? 

Like much of the Glendale area, the Grayson Power Plant site is located within a liquefaction hazard zone. A site-specific geotechnical study for the repowering project was performed and included analysis of both seismic and liquefaction risks. The geotechnical study included recommendations for project design in conformance with applicable building codes, which include considerations for seismic and site-specific liquefaction hazards. 

The site has been the home to the City’s local generation for over 75 years and has been subjected to several major earthquakes, including the Sylmar and Northridge earthquakes. Notably, GWP has been able to restore electricity to its customers faster than any other nearby city or Southern California Edison, in part due to having local units at Grayson that were either already operating or were started up, due to seismically-induced loss of transmission imports. 

Why can’t GWP just have solar panels and batteries to power Glendale?

GWP has reviewed the feasibility of solar PV with battery storage before and also considered solar PV with battery storage as a project alternative. GWP found that such a system is not feasible because of physical constraints. Glendale does not own or control sufficient real estate to develop a utility-scale solar with sufficient capacity coupled with energy storage to reliably serve Glendale’s power needs. Obtaining the required capacity through rooftop solar would be significantly more costly than the proposed repowering project and the pace of rooftop solar development is not rapid enough to replace the need for the Project.  Additionally, GWP does not control private rooftops within Glendale. For these reasons solar with battery storage was not considered a feasible alternative to meet Glendale’s current needs. However, we continue to pursue other renewable energy options, including solar power and battery storage as part of the integrated plan to meet the city’s energy needs. Through the efforts of private individuals, businesses and GWP, almost 15 MW of rooftop solar PV capacity has been developed within Glendale over the past 10 years and GWP has installed a 2 MW battery energy storage system at its Grandview Substation.

Can Scholl Canyon be used as a solar site?

GWP partnered with a private developer two years ago to study the possibility of developing a solar project at Scholl Canyon. The developer determined that the site constraints at Scholl Canyon made it unsuitable for solar development. For example, the existing environmental control systems for the landfill are required even for a closed landfill (these systems gather methane gas that would otherwise escape to the environment, a gas that has a global warming potential 21 times greater than CO2). Those systems require continued access, which consequently limits the land available for solar panels. In addition, the landfill is subject to significant settlement, which would take the solar panels out of alignment, as well as complicating the electrical gathering system design, necessitating regular rebuilding and realignment.

Will the repowered plant increase air pollution in the area?

The permitted emissions from the Grayson Repower project will be less than the permitted emissions from the existing Grayson Power Plant. 

GWP developed emissions estimates for the Grayson Repower to use as a basis for permitting. The permitting process is based in part on the worst case daily emission and peak season monthly emissions coupled with the need to provide sufficient starts and operating hours for possible contingencies. Even with these conservative estimates, the permitted emissions from the repowered plant would be less than the permitted emissions from the existing plant.

Demolition of the existing facility and soil remediation will take 9 months. How are you making sure no contaminants if any are emitted into the air?

During demolition of the existing facility, waste removal plans will be developed and implemented to ensure that no lead or asbestos or other known contaminants are emitted into the atmosphere. Demolition will be done in accordance with applicable federal, state and local requirements. These requirements address containment and handling of materials, as well as a monitoring plan to ensure compliance. These requirements are not specific to the demolition of a power plant; they apply to all demolition work. The contractors we will use are licensed to do this type of demolition and meet these requirements.

EPC Contractor Short List


The following are the EPC proposers that were selected to receive the Request For Proposals for the Proposed Grayson Repowering Project:

Haskell Corporation
Joe Spink

Kiewit Power Constructors Co.
Patrick Sparks

MasTec Power Corp.
Michael DonMoyer

PSC Primoris - ARB, Inc.
Phill Reed


The EPC RFP is scheduled to be released in August, 2017.




Draft EIR


Click here to view the whole Draft Environmental Impact Report (DEIR) for the Grayson Repowering Project. The DEIR is also broken down by sections below.

The original 45 day review period was from September 18, 2017 through November 3, 2017. The City of Glendale extended the review period until November 20, 2017.

Click here to view FAQs for the Grayson Repowering DEIR.

Click here to view the Power Point from GWP's Special Commission Meeting on the DEIR.

Click here to view the DEIR Notice of Availability
Click here to view the DEIR Notice of Availability for the comment period extension



























NOP / IS Comments


2/6/18 Pres. to City Council


Contact Us


City of Glendale Water & Power

141 N. Glendale Avenue, Level 4

Glendale, California 91206

Send Us A Message

What's + ?







Share this site